Biosphere concept
The Biosphere concept refers to the global sum of all ecosystems, encompassing the regions of the Earth where life exists. It is one of four major spheres—alongside the lithosphere (land), atmosphere (air), and hydrosphere (water)—that interact to support life. Key components of the biosphere include essential compounds such as hydrogen, oxygen, carbon, nitrogen, potassium, and sulfur, which cycle among these spheres to sustain living organisms. Water, a critical element for life, moves through the ecosystem via the hydrologic cycle, influencing various biomes and their characteristics based on annual precipitation levels.
Solar energy serves as the primary energy source for the biosphere, driving processes like photosynthesis in plants, which convert carbon dioxide and water into organic material and oxygen. This energy also plays a vital role in the water cycle and the formation of weather patterns. The distribution of solar energy varies across the planet due to its curvature, resulting in different climates characterized by temperature and precipitation. Understanding the biosphere is essential for studying the interconnectedness of life and the environmental factors that sustain it.
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Subject Terms
Biosphere concept
Categories: Ecology; ecosystems; environmental issues
Compounds of hydrogen, oxygen, carbon, nitrogen, potassium, and sulfur are cycled among the four major spheres, one of which is the biosphere, to make the materials that are essential to the existence of life. The other spheres are the lithosphere, the outer part of the earth; the atmosphere, the whole mass of air surrounding the earth; and the hydrosphere, the aqueous vapor of the atmosphere, sometimes defined as including the earth’s bodies of water.
The Water Cycle
The most critical of these compounds is water, and its movement among the spheres is called the hydrologic cycle. Dissolved water in the atmosphere condenses to form clouds, rain, and snow. The annual precipitation for any region is one of the major factors in determining the terrestrial biome that can exist. The precipitation takes various paths leading to the formation of lakes and rivers. These flowing waters interact with the lithosphere (the outer part of the earth’s crust) to dissolve chemicals as they flow to the oceans. Evaporation of water from the oceans then supplies most of the moisture in the atmosphere. This cycle continually moves water among the various terrestrial and oceanic biomes.
Solar Energy
The biosphere is also dependent upon the energy that is transferred from the various spheres. Solar energy is the basis for almost all life. Light enters the biosphere as the essential energy source for photosynthesis. Plants take in carbon dioxide, water, and light energy, which is converted via photosynthesis into chemical energy in the form of sugars and other organic molecules. Oxygen is generated as a by-product. Most animal life reverses this process during respiration, as chemical energy is released to do work by the oxidation of organic molecules to produce carbon dioxide and water.
Incoming solar energy also interacts dramatically with the water cycle and the worldwide distribution of biomes. Because of the earth’s curvature, the equatorial regions receive a greater amount of solar heat than the polar regions. Convective movements in the atmosphere—such as winds, high- and low-pressure systems, and weather fronts—and the hydrosphere—such as water currents—are generated during the redistribution of this heat. The weather patterns and climates of earth are a response to these energy shifts. Earth’s various climates are defined by the mean annual temperature and the mean annual precipitation.
Bibliography
McNeely, Jeffrey A. Conserving the World’s Biological Diversity. Washington, D.C.: International Union for Conservation of Nature and Natural Resources, 1990. Covers strategies being used to conserve the biosphere around the world.
Smith, Vaclav. Cycles of Life: Civilization and the Biosphere. New York: W. H. Freeman, 2000. Introduction to biogeochemical cycles. Explains the interrelationship of carbon, nitrogen, sulfur, and living organisms as agents of change in the environment.
Vernadskii, V. I. The Biosphere. Translated by Mark A. S. McMenamin. New York: Copernicus, 1998. Reviewed as required reading for all students in earth and planetary sciences. Describes life as a cosmological phenomenon and a means by which energy is stored and transformed on a planetary scale.
Weiner, Jonathon. The Next One Hundred Years: Shaping the Fate of Our Living Earth. New York: Bantam Books, 1991. Discusses threats to the earth’s biosphere.
Wilson, E. O., ed. Biodiversity. Washington, D.C.: National Academy Press, 1988. Contains articles from noted biologists on topics about biodiversity and problems facing biodiversity in biomes.